1. Field of the Invention
The present invention is directed to dishwashers and more particularly, to dishwasher spray arm feed systems.
2. Description of the Related Art
Modern dishwashers include a tub and an upper and lower rack or basket for supporting soiled dishes within the tub. A pump is provided for recirculating wash liquid throughout the tub to remove soils from the dishes. Typically, larger dishes are carried on the lower rack or basket which is moveable in or out of the tub for loading and unloading. A lower wash arm that rotates about a vertical axis is provided beneath the lower rack. An upper rack is also provided for articles such as cups and glasses, and it is mounted on rollers and tracks to also be moveable in or out of the tub for loading and unloading. It has been found that a single rotary lower wash arm does not always give good washability performance because the spray path can be blocked by dishes on the lower rack and very little water may reach some articles on the upper rack. Therefore, nearly all dishwashers include an upper or second level spray mechanism beneath the upper rack to spray upward directly on the articles in the upper rack and downwardly on to the articles on the lower rack.
Lower spray arms are generally mounted directly above the recirculation pump and receive wash liquid directly therefrom. Different approaches have been taken to rotatably support a lower spray arm and provide a thrust bearing surface. For example, U.S. Pat. Nos. 3,866,837 and 5,427,129 disclose different spray arm bearing support systems.
The upper or second level spray system may include a rotating wash arm similar to the main or lower wash arm which may be mounted directly to the upper rack and receive wash liquid through an upper arm feed system. Different approaches have been taken to feed and rotatably support second level spray arms which are associated with an upper rack or basket. One approach for an upper arm feed system is to utilize a tower mounted to the lower rack which receives wash liquid from the lower spray arm and has an open upper end such that wash liquid is sprayed through the tower upwardly into a bottom inlet in the upper spray arm for supplying the upper arm with wash liquid. U.S. Pat. No. 5,330,102 discloses a center tower type system for feeding an upper spray arm having a bottom inlet.
Another approach to supplying wash liquid to an upper rack spray system is to feed wash liquid to an upper spray arm through a liquid conduit which is mounted on the exterior of the dishwasher tub. U.S. Pat. Nos. 4,172,463, 4,004,600 and 5,211,190 are all examples of this type of approach. Generally, a discharge outlet from the wash pump is provided which is connected to an liquid conduit which is routed along the exterior of the dishwasher tub. The liquid conduit passes through the tub back into the wash chamber in an area near the upper rack to feed wash liquid to the upper spray arm.
The upper spray arm of a dishwasher may also be fed through the use of an internally disposed supply conduit. In such case, the wash pump of a dishwasher may be provided with a discharge outlet for supplying a conduit which extends along the inside surface of the dishwasher tub to a location near the upper dishwasher rack to feed wash liquid to the upper spray arm.
Upper dishracks are often supported in a manner that allows for vertical height adjustment. U.S. Pat. Nos. 5,474,378 and 4,097,099 illustrate adjustable upper rack support systems.
Adjustable upper racks require upper spray arm feed systems which can accommodate the adjustable position of the upper rack. In the past various upper rack feed system designs have been used which can accommodate variable position upper racks. For example, U.S. Pat. No. 5,823,211 discloses a dishwasher having at least one adjustable height rack or basket to which an associated spray arm and inlet tube are secured. The inlet tube is disposed horizontally and is connected by a coupling to a supply line secured to a side wall of the tub. An open connection fitting and two closed blind fittings protrude toward the inlet tube. The coupling has two openings into which the connecting fitting and one of the blind fittings respectively, protrude. The adjustable basket can be moved between an upper and lower position wherein the open connection fitting supplies wash liquid to spray arm associated with the adjustable height rack.
EP 0 401 767 B1 is also directed to a feed system for supplying liquid to a spray arm associated with an adjustable height basket. In this reference, the upper spray arm is equipped with a connecting pipe extending horizontally toward the back wall of the tub and adapted to join up in a detachable fashion with a water supply pipe extending vertically in correspondence with the back wall of the tub. To supply the upper spray arm with wash liquid in each of two vertical positions, the connecting pipe is designed at one end with a box collector extending upward and equipped with two vertically spaced outlets. The collector is provided with check ball type valve means adapted to make the supply pipe communicate only with the outlet of the collector which is coupled with the connecting pipe.
The present invention provides a dishwasher having a wash chamber or tub including a sump and a side wall. A pump is fluidly connected with the sump. At least one adjustable height basket is supported within the tub. A supply tube is supported adjacent the tub side wall and receives wash liquid from the pump, the supply tube has a manifold portion including a plurality of outlet openings. A coupling retainer is connected to the supply tube and has a plurality of funnel shaped coupling ports corresponding in number and spacing to the outlet openings of the supply tube. Each of the coupling ports includes a center opening which is provided with a sealing surface. A valve member supports a plurality of valve elements for sealing the outlet openings and is captured between the coupling retainer and the supply tube such that the valve elements generally align with the coupling ports. A spray arm is associated with the adjustable height basket and has a feed tube extending toward the supply tube. The feed tube has a coupling end wherein the coupling end is insertable into one of the coupling ports for fluidly connecting the feed tube to the supply tube. The coupling end is sealingly engaged by the sealing surface upon insertion into one of the coupling ports and opens the valve element corresponding to the coupling port into which the coupling end is inserted. Water pressure within the manifold is used to seal the coupling ports which do not receive the coupling end.